In a conventional system, since its internal electronic element is a large heat source, and the performance of the internal electronic element degrades with the increase of the temperature thereof, the heat generated thereby has to be quickly removed so as to keep the internal electronic element's regular performance. Therefore, a blower having high air pressure is commonly used to achieve the objective of rapidly dissipating heat.
Conventionally, a fan with high air pressure is known as a centrifugal fan or blower. Please refer to both FIG. 1 and FIG. 2, the conventional impeller 100 has a hub 102, fan blades 104 and a rib 106. The rib 106 is disposed and connected between the fan blades 104 and the hub 102. The curvatures of the surfaces 108 and 110 (i.e. a windward side and a leeward side) of the fan blade 104 are the same and can be considered as two concentric arcs, which means the thickness of the fan blade 104 is uniform.
While the performance of an electronic element is enhanced, the heat generated by the electronic element is also greatly increased accordingly. Hence, the rotational speed of the conventional blower used has to be greatly increased so as to obtain the desired air pressure and air flow. However, when the rotational speed is increased, the noise level generated thereby raises correspondingly.
Although the noise level can be reduced by lowering the rotational speed of the conventional blower, the heat generated by the aforementioned electronic element can't be removed completely due to the less air flow and air pressure thereof.